Wattpic
Wattpic is a company that is dedicated to the design and development of solar trackers of single and double axle.
http://www.wattpic.com/default_eng.htm

Solartiva
Solartiva sg3/sg4 is a solar tracking system with two axles with a single engine. Compact and lightweight design for modular and expandable mounting. Adaptable to any inclination and orientation on which is built the industrial area or rooftop.
http://www.solartiva.com/